Yesterday, the Irish singer-songwriter penned an open letter to the 20-year-old pop star in which she expressed her concern over Miley's controversial image after learning that the erstwhile Disney star wanted her "Wrecking Ball" music video to be similar to her own famous hit, "Nothing Compares 2 U."

In Sinéad's missive, the 46-year-old singer-songwriter suggested Miley is allowing herself to be "pimped" by the music industry, which then prompted the "We Can't Stop" singer to post a series of Sinéad's tweets (which the veteran claims are two years old) and compare her to Amanda Bynes.

And it's safe to say Sinéad received Miley's latest memo, as she took to her Facebook page to pen a third letter (no, seriously) to the singer.

"I have no interest whatsoever in meeting you," the "Foggy Dew" crooner began. "You had plenty of time yesterday to abuse Amanda Bynes..an entirely innocent party.. and myself.. who also did nothing to deserve your abuse.. along with every other sufferer of mental health problems and every person who suffered abuse at the hands of priests," she wrote, referencing the photo Miley tweeted yesterday of Sinéad ripping up a picture of the Pope during a musical performance on Saturday Night Live years ago.

"You can take five minutes today between g- string f--kin' changes to publicly apologize and remove your abusive tweets," she added. "If you do not then you don't give a s--t who you mock and what damage you do by being so ignorant."

"When you publicly apologize to Amanda and myself and all mental health sufferers as well as all who were abused by priests that will end the matter as far as I am concerned," she wrote. "What you did yesterday was designed to damage me and my career and has caused me enormous distress and harassment and has potential to damage my career, since you deliberately gave the impression those tweets of mine were not two years old but reflect my current condition."

And then she threatened to take legal action against the former Hannah Montana star (again).

"If you cannot apologize I will have no choice but to bring legal proceedings against you since it is extremely hard to be given work when people think one is suffering from mental illness," she said. "I have no interest in or desire to cause you trouble but if you do not apologize for having deliberately tried to cause me hurt and trouble personally and professionally I will have to bring pressure upon you."

Of course, that's not all Sinéad had to say.

"When you end up in the psych ward or rehab I'll be happy to visit you.. and would not lower myself to mock you," she continued. "Be a proper woman and make the public apologies I have listed above. Your hosting SNL is a bulls--t reason for not taking five minutes to do the right thing and your behavior yesterday will rebound upon you very badly.

"You have no business abusing Amanda Bynes or anyone else. How do you think you made her feel yesterday?," she wrote before referencing Miley's BFF, Britney Spears. "How do you feel when your friend Britney Spears is mocked and humiliated for having had mental health problems? I know I personally want to bash those who treat her that way. If she is your friend and more importantly if you are a true friend to her.. you ought apologize for joining those who mock and humiliate women who have been too nice frankly, to manage the music business without sensibly losing their minds."

She continued with her "anti-female" commentary before (finally) singing off.

"Cease behaving in an anti-female capacity," she wrote. "You will become the victim of it shortly. Soon it will be you the media 'crazy' .. and you will not enjoy it.. and you will appreciate people (like myself) standing up for you. Which I will be happy to do.. if you earn my respect today by apologising publicly."

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